Use the physical-pixel space for native IME on linux platform.

chrome/browser/ui/views/ime_driver/remote_text_input_client.cc

Index: chrome/browser/ui/views/ime_driver/remote_text_input_client.cc
diff --git a/chrome/browser/ui/views/ime_driver/remote_text_input_client.cc b/chrome/browser/ui/views/ime_driver/remote_text_input_client.cc
index b7705ad069c5ea3fad273b43d4117cb752bdd6e1..9f4e2ac039b8f55ad26bd6072aa864e13708f9f8 100644
--- a/chrome/browser/ui/views/ime_driver/remote_text_input_client.cc
+++ b/chrome/browser/ui/views/ime_driver/remote_text_input_client.cc
@@ -69,6 +69,10 @@ bool RemoteTextInputClient::CanComposeInline() const {
   return true;
 }
 
+float RemoteTextInputClient::GetScaleFactor() const {
+  return 1.0f;
+}
+
 gfx::Rect RemoteTextInputClient::GetCaretBounds() const {
   // TODO(moshayedi): crbug.com/631527.
   NOTIMPLEMENTED();